Increased Knee Range of Motion Following Rectus Femoris Transfer Does Not Improve Walking Ability in Patients With Cerebral Palsy

BACKGROUND: Rectus femoris transfer (RFT) outcomes in cerebral palsy (CP) are often analyzed using 3-dimensional gait analysis, but there is limited patient-reported data on this procedure. This study aimed to evaluate the relationship between changes in walking ability, measured by the Functional Assessment Questionnaire (FAQ), and knee range of motion (KRM) improvements following distal RFT in CP. METHODS: Data from a gait laboratory database (January 2002 to April 2022) were reviewed. Patients with spastic diplegic CP classified as GMFCS levels I to III who underwent RFT with pre- and postoperative gait analyses were included. Ninety-eight patients met the criteria and were divided into 3 groups based on KRM changes post-RFT: (1) reduction (RG): decrease >1 SD, (2) unchanged (UG): changes within ±1 SD, and (3) improvement (IG): increase >1 SD. Demographics, kinematics, the Gait Deviation Index (GDI), and FAQ scores were analyzed and compared among groups. RESULTS: Postsurgery, KRM decreased in 6 patients (6.1%), remained unchanged in 69 (70.4%), and improved in 23 (23.5%). RG was excluded from comparisons due to the small sample size. There were no significant between-group differences in age at surgery (UG: 14.32 y; IG: 14.32 y), follow-up duration (UG: 3.17 y; IG: 2.70 y), change in GDI (UG: +8.14; IG: +11.07), increase in peak knee flexion during the swing phase (UG: +6.44 degrees; IG: +7.34 degrees), or change in walking ability as measured by the FAQ (UG: +0.79; IG: -0.08). In contrast, minimum knee flexion during the stance phase decreased in IG (-14.32 degrees) and increased in UG (+4.78 degrees), with a significant between-group difference (P<0.001). The prevalence of surgical procedures performed concomitantly with RFT was similar between the UG and IG groups, except for surgical lengthening of the hip adductors, which was observed in 13% of patients in UG and 34.8% in IG (P=0.02). CONCLUSIONS: Improvements in kinematic parameters alone may not predict patient-reported functional gains. In the present study, increased KRM after RFT was not associated with improved FAQ walking ability, as FAQ scores were similar regardless of whether KRM increased. LEVELS OF EVIDENCE: Level III.